Improvement in ratchet-drills



MT1-3D STATES PATENT' Erice;

|MPaovEMENT IN aATcHET-DRILLS.

Specification forming part of LettersPatent No. l12,560, dated May 3,1864.

To all whom it may concern:

Be it known that I, J oHN C. CHAPMAN, of Charlestown, in the county ofMiddlesex and State of Massachusetts, have invented certain new anduseful Improvements in Ratchet- Drills, of which the following is afull, clear, and exact description, reference being had to theaccompanying drawings, making part of this specification, in which-Figure 1 is a perspective View of my improved hand-drill. Fig. 2 is avertical longitudinal section through the same.

In operating ratchet hand-drills as at present constructed aconsiderable loss of time and great inconvenience is occasioned infeeding, especially in confined or narrow places, as the workman isobliged at frequent intervals to insert the end of a small rod into oneof the holes at the top of the feeding-shaft to turn it va little foreach feed, it being impracticable to attach a wheel or other projectingdevice to this shaft on account of the confined positions in which thesedrills are generally employed, and these drills are also liable tobecome unsteady when the feedingshaft is nearly screwed out to its fullextent.

My invention has for its; object to avoid these difficulties, and toproduce a self-feeding drill that shall be more steady and durable thanthose now in use; and it consists in causing' the feeding-shaft (whichis hollow and works on a screw projecting up from the drill-socket) toslide with a spline and feather in a hollow sleeve, to the lower end ofwhichV is attached a ratchet-wheel, operated by a pawl attached to thehand-lever which operates the drill, by which arrangement of parts, asthe drill is operated, the hollow sleeve is rotated independently of thedrill, carrying with it (by means of the spline and feather) thefeedingshaft, which is thus raised on the screw-shaft to effect the feedas frequired. Theghollow sleeve, in combination with the screw-shaft,also serves as a support for the feeding-shaft, by which the drill isrendered more steady and durable than any now in use with which I amacquainted.

To enable others skilled in the art to understand and use my invention,I will proceed to describe the manner in which I have carried it out.

In the said drawings, A is the hand-lever,

which is enlarged at one end, so as to encircle the standing part ordrill-socket, B, to which is attached a ratchet-wheel, C, with whichengages a spring pawl, a, attached to the lever, bywhich means thedrillis rotated as the handle is vibrated, in a well-known manner.

D is a hollow sleeve, which iits over and incloses a screw-shaft, E,projecting up from the drill-socket B, the interior of the sleeve beingof such a diameter at the bottom as to tit the lower end of the shaft E,where it is secured in place and prevented from being raised by ascrew-nut, b, which works in the shaft E, and when in place rests on theshoulder c on the interior surface of the sleeve D, as seen in Fig. 2. Aleft-hand screw-thread is cut on the shaft E, on which works the hollowfeeding-shaft G. This shaft is provided at its upper end with a steelpoint, 3, in the customary manner, and is made to exactly fit theinterior diameter of the sleeve D, in which it slides with a spline andfeather, e, on each side, as seen in Fig. 2, which prevents thefeeding-shaft and holl w sleeve from being turned independently of eachother, and the'v dust and chips are also eifectually excluded from theworking parts.

To the lower end of the hollow sleeve D is attached a ratchet-wheel, H,the neck of which projects into the hollow sleeve D, where it -issecured by a pin or screw, 4, forming a shoulder, as before described,this wheel being operated by a spring-pawl,f, on the handle A. The wheelH is furnished with nearly twice the number of teeth that are on thewheel C, but the'number may be varied according to the amount of feedrequired. It will thus be seen that on the commencement of the vibrationof the handle A in the direction of the arrow 5 the ratchet-wheel H, andwith it the hollow sleeve D, will be carried forward by the pawl fashort distance before the pawl a commences to move the ratchet-wheel ICand and drill, thus revolving the feeding shaft G by means of .thespline and feather e, which causes it to rise on the screw shaft IIE,and effect the feed as required.

If a different feed is required, the ratchetwheel H may be taken off andreplaced by one having a different number of teeth. In some cases, aswhen the hole is nearly bored through, the pawl fmay be disengaged fromthe wheel H and the sleeve D revolved by hand, or the feeding-shaft maybe turned by a rod inserted into a hole in its upper end in the ordinarymanner. r

It will be seen that the hollow sleeve D, in connection with the screwE, serves as a support for and steadies the feeding-shaft G when screwednearly out, thus rendering the drill stift' and preventing it fromshaking, which is a serious objection to those now in use, and alsoincreasing its durability.

If desired, the ratchet-Wheel H may be dispensed with and the feedingeffected by turning the sleeve D by hand, and the advantages ofsteadiness and durability above described still be retained, in whichcase it would be preferable to have a right-hand thread cut upon theshaft E, as it would be then4 more convenient-to turn the sleeve to theleft.

A right-hand threadon the shaft Ev might also be employed with theratchet-Wheel H but in that case the drill would be left-handed What Iclaim as my invention, and desire t secure by Letters Patent, is

1. A self-feeding ratchetdrill, in which th feedingashaft G is thrustout from an eXterio sleeve, D, by revolving the sleeve by a ratche andpawl operated by the hand-lever A, sub stantially as set forth.

2. The hollow sleeve D and feeding-shaf G, sliding therein with a splineand feathe in combination with the screw-shaft E, ope ating in themanner-'and for the purpose su stantially asdescribed. v J. C. CHAPMAN.'Witnesses:

P. E. TEsCHEMAoI-IER, N. W. STEARNS.

